Brilliant improvisers, entrepreneurs don’t start out with concrete goals. Instead, they constantly assess how to use their personal strengths and whatever resources they have at hand to develop goals on the fly, while creatively reacting to contingencies.

Inc. summarized it well: "Do the doable, then push it."

That is not to say entrepreneurs don't have goals, only that those goals are broad and—like luggage—may shift during flight. Rather than meticulously segment customers according to potential return, they itch to get to market as quickly and cheaply as possible, a principle [Sarah] Sarasvathy [a professor at the University of Virginia's Darden School of Business] calls affordable loss. Repeatedly, the entrepreneurs in her study expressed impatience with anything that smacked of extensive planning, particularly traditional market research. (Inc.'s own research backs this up. One survey of Inc. 500 CEOs found that 60 percent had not written business plans before launching their companies. Just 12 percent had done market research.)